Members of the Antigo Fire Department took the Ice Busket Challenge this week, adding to the coffers of the ALS Association.

In between ambulance runs, the firefighters and parademics were doused by the fire engine’s big deluge gun, assuring a thorough soaking with some icy water. And they challnged the city of Antigo Police Department, street department, City Hall employees including Mayor Bill Brandt and City Administrator Mark Desotell, and all Langlade Hospital employees to do the same.

Approaching $100 million, the viral fundraising campaign for the ailment better known as Lou Gehrig’s Disease has put the ALS group into the top ranks for medical charity donations. Since the end of July, the money has been sloshing in at a rate of about $9 million a week. Last year, from July 29 to Aug. 26, the group raised just $2.6 million.

It’s caught everyone off-guard, none more so than the ALS Association folks. But they know this is likely a one-off phenomenon, and the group now faces the task of spending all that money wisely. Research, care and advocacy are the group’s three main missions — but officials say they don’t know yet exactly how they’ll use the astonishing windfall.

“I think even if I or any PR person at either a non-profit or a for-profit company had all of the PR dollars in the world to invest, no one would have come up with this idea,” Carrie Munk, the association’s spokeswoman, said. “We realize there are responsibilities that come with being good stewards of these dollars.”

Part of what’s surprising is that ALS — or amyotrophic lateral sclerosis — is one of those “orphan” diseases. It is a neurodegenerative disease that causes paralysis and death, and the association estimates that about 5,600 new cases are diagnosed in the U.S. each year.

This campaign hasn’t exactly put the charity in the same neighborhood as giants like the American Cancer Society, the American Heart Association or Susan G. Komen for the Cure — which raised $889 million, $529 million and $310 million last year, respectively. But it’s moving into the same ZIP code now.

“People who have been in this space for a long period of time feel like it’s a dream come true,” Munk says.

In case you’ve been under the proverbial rock, here are the basic rules: Someone issues a challenge — that you allow yourself to be doused with a bucket of ice and water, like winning coaches along the sidelines. Then, the challengee has 24 hours to make a $100 donation to the ALS Association or submit to the water torture. In some instances, the Ice Bucket dunker still donates $10, and, of course, in all cases, additional dollars are encouraged.

In the last month, everyone from Microsoft co-founder Bill Gates to former President George W. Bush has been doused. The Internet and airwaves are awash in videos of people taking the challenge — even if they fully intend to write the check.

Jonah Berger, author of the book “Contagious: Why Things Catch On,” says it’s like a modern-day chain letter — except, in this case, everyone will know if you break the chain.

“It has a lot of the key ingredients that often make people want to share things,” Berger, a marketing professor at the University of Pennsylvania’s Wharton School, says. “It gives people lots of social currency to be part of it. It makes you look good. It makes you look smart and in the know; you know what’s going on. And it’s always hard to back down from a challenge.”

Antigo firefighters and paramedics wince as they take the Ice Bucket Challenge this week.